This invention relates to solvents and more particularly to cleansing solvents for removing medical adhesives from the skin.
Adhesives are routinely employed to secure medical devices such as non-adherent dressings and catheters to the skin as well as for adhesive dressings. Removal of the device or dressing may leave residual traces of adhesive on the skin. Adhesive residues can be a nuisance particularly if it is required to re-affix a device at the same skin site. Moreover skin trauma may occur when an adhesively secured device is removed. Solvents are traditionally used to facilitate removal of both the adhesive product or device and any remaining residues.
Many solvents act as defatting agents and can cause skin irritation. Irritation and skin trauma is especially prevalent where adhesive products have to be applied repeatedly to the same skin site.
Additionally many of the traditional solvents are flammable and are considered to be dangerous safety hazards.
The most common types of medical pressure sensitive adhesives used for attachment to the skin are based upon two different molecular species. These are the polyisobutylene polymers and polyacrylate copolymers. Typical formulae for polyisobutylene based adhesive systems used for medical devices are described in U.S. Pat. Nos. 3,339,546 and 4, 253,460. Polyacrylate adhesives frequently applied to the skin in the form of plastic tapes, bandages, transdermal medical delivery systems and the like are described in U.S. Pat. Nos. 3,691,140 and 4,420,470.
The polyisobutylene polymers have a solubility parameter of about 7.5 cal 1/2/cm 3/2 (reference CRC Handbook of Solubility Parameters and Other Cohesion Parameters, Barton, 4th Edition 1988, pg 282). The polyacrylate adhesives exhibit approximate solubility parameters of 12 to 13 cal 1/2 cm 3/2. Due to the significant difference in solubility parameters between polyisobutylene polymers and the polyacrylate copolymers it would be expected that different incompatible solvent systems would be required to dissolve either of the two polymers. Thus, polyisobutylene is readily soluble in solvents such as hexane or toluene whereas the polyacrylates are readily soluble in esters such as ethyl acetate or ketones such as methyl ethyl ketone. We have now found that the disadvantages of the prior can be mitigated by the use of a single solvent. This invention offers one simple solvent system containing medically safe solvents capable of aiding the removal of adhesive medical devices and their associated adhesive residue from the skin irrespective of whether the adhesive is a polyisobutylene based system or a polyacrylate copolymer based system.